This invention relates generally to footing/foundation forms for the construction of concrete foundations, and more particularly to such forms having integral drainage systems including a plurality of hollow tubes elevated to grade above an excavation bottom and supported at that level by a plurality of stakes.
Typical building practice requires construction of a footing or foundation upon which vertical concrete walls of a structure rest. A typical outer wall may range from 6-12 inches in thickness and the footing upon which the walls rest is typically wider than the wall width and may have a vertical depth (height) of 6-12 inches. Because these foundations are commonly a substantial distance below ground level, accumulation of water with a head of pressure at the footing level is a problem. To prevent this ground water from entering the building through floor or foundation cracks, or through crevices between the foundation and basement floor, good building practice provides a means for removing the undesired ground water. Standard procedures have developed over the years to construct sturdy footings/foundations and to provide a drainage system to remove future unwanted ground water.
The standard procedures include preparing a trench or excavation to the appropriate depth and dimensions to accommodate the footing/foundation forms and drainage system. Next, the inside and outside corner points of the footing/foundation wall are surveyed and a string or chalk line is placed around the intended footing/foundation perimeter. Historically, planks of seasoned wood were arranged along the surveyed line and secured in place by stakes. Because foundation forms are typically a pair of serpentuitous parallel walls, the prior art planks were cut to appropriate lengths using either mitered ends or special corner pieces to maintain the parallel relationship throughout the footing/foundation perimeters. After completing the entire footing/foundation network, concrete was poured between the forms, appropriately screeded, and allowed to set. When the concrete was sufficiently hard (typically the next day), the forms were removed. Once the forms were removed, a certain amount of re-trenching was required to remove accumulated backfill and debris. Then, after re-trenching, an independent drainage system was installed. It was also customary to place gravel or filler stone around and over the drainage system to create a leach field to facilitate proper draining.
Recognizing the costs associated with the highly labor intensive prior art footing/foundation construction techniques (i.e. excavating, installing forms, pouring the footing, removing the forms, re-trenching, constructing the drainage system, laying a gravel leach field, and backfilling the excavation), attempts have been made to minimize these costs. However, many of these attempts have failed to adequately minimize costs because the methods employed required custom designed materials which to a substantial degree offset labor savings with an increase in material costs.
Many of the problems associated with prior art forms were overcome by the footing/foundation form disclosed and claimed in U.S. Pat. No. 5,586,416 (the '416 patent), which is commonly owned by the inventors herein. The disclosure of the '416 patent is incorporated herein by reference.
The footing/foundation form disclosed in the '416 patent has two substantially parallel spaced apart, serpentuitous walls, each wall including a plurality of hollow tubes elevated to grade above an excavation bottom by stake and clip mechanisms with gravel filled between the elevated tubes and the excavation bottom. The tubes are connected end-to-end and include a plurality of holes to enable water accumulating adjacent the footing/foundation to drain into a sewer, dry well, or sump pump. However, unlike other prior art forms having integral drainage means, the tubes of the '416 patent are preferably standard 10-foot PVC round tubes available at many hardware and construction stores or are easily adapted from commonly available PVC tubes. The stakes of the '416 patent are pieces of reinforcing bar (or other steel rods which are readily available) and the clips are also manufactured from inexpensive materials.
Once the tubes of the '416 patent are elevated to grade, the clips are frictionally and resiliently engaged to the stakes and the tubes to secure the tubes to grade. After the form is constructed, further adjustments in the elevation of the tubes is accomplished by driving the stakes further into, or pulling them out of, the ground.